1. Field of the Invention
The present invention relates to devices for the formation of sonar channels having a wide frequency band. These channels are formed by compensating in each channel for geometrical delays of signals received by the different sensors which form the sonar transducer array. The invention relates to formation of channels by digital techniques.
This invention is more particularly applicable to a ship or submarine sonar system in which provision is made for an acoustic transducer array having little or no symmetry.
2. Description of the Prior Art
It is a known practice to form so-called angular or spatial channels for a sonar transducer array having N sensors by means of a digital device comprising means for storing signals, an address computer and a summing device. The N signals received by these sensors are digitized and multiplexed. In a first step, the digital samples are written in a volatile memory of the random-access or RAM type. A predetermined number P of groups of N successive samples are thus written at the corresponding NP addresses. In a second step, the delayed samples are read in said memory at the correct addresses by means of the computer and are summed so as to form a channel.
In order to form a large number of channels by means of this prior-art device, it is necessary to employ a large number of formation circuits in parallel.